I had sex june 10, i have had 2 withdrawal period since than and a negative pregnant blood test 28 days after sex. chances of pregnancy still? on bc

Tests are accurate: Blood or urine pregnancy tests are very accurate and not affected by foods, herbs, common illnesses, sexually transmitted diseases, or medications. A correctly done urine test gives a reliable result 3 weeks after sex (3 weeks after when conception might have happened) or 1 week after missing a menstrual period or a withdrawal period. Thus, pregnancy in this case is very unlikely.